Interchangeable letter display device



Feb. 19, 1952 c. N. DICKEY INTERCHANGEABLE LETTER DISPLAY DEVICE FiledSept. 20, 1947 v swam: TAV mm: STEAK $2.569

INVENTOR. CHARLES N. DICKEY.

ORJVEY'S.

Patented Feb. 19, 1952 STATES INTERCHANGEABLE LETTEREDISPLAY DEVICECharles N.'Dickey, Northville, Mich., assignor, by "1 mesne;assignments, to James'S. Cushman, New .:York, N. Y., and Harold F.Moonert, "Wil- .ApplicationSeptember 20, 1947,Serial No." 775,229

2 Glaims.

. 1 'Ihisinvention relates to a display device for interchangeableletters and "decorative material and for "design-element's for assemblyupon the 'surface 'or'suitable background without special preparation ofthe surface orseparate fastening :device for the display elements.

There havel'beenmany attempts to provide .zinterchangingdevices of thischaraoter'because -oftheir iinherent usefulness to businessestztb-:Jlishments such :asrestaurants, retail stores, de-

wherein the objects aremaintainedion the panel byrstaticrelectricalenergy. This. arrangement is -notdependable and. the letters are ofexceedingly thin flexible material because of thesmallmagnitude. :of'the" retaining force.

It: .is an object .of this invention to produce L IBttEI'ST of such anature that they-iwill be; retained 'xon alsmoothhardsurface withoutthe. use' ofad- -hesive 'crude'rubber facings, adhesives, felt..pads,water :films, slotted, grooved or specially constructed supportingsurfaces, or vacuum cups, and

which will remain. in;:place indefinitely. This I"accomplish-byforming;the letters ofisheetri'flex- 1 :ible, rubber-liker'plastic material which 1 may :be formedasirather thin sheetsbut whichmayaalso comprise arlaminated articlehaving a :facingsof --the1rubberelikermaterial described :backed up by clothpmetal,plywood-orthejike. Theiundersides :of the.letters'zoridisplay elements;in e.,* the sides serving to mount them, are formed witha smooth"polished: surface. iLetters ofithis; type whenrap- "plied to a support.panel haveaa asmooth polished surface will remain firmlyx adherent tothe support-until the user desires toremovethem. The letters are readilyremoved .by merely peeling them off therpanel, but the force:of:gravityand the 1 action :of. air-currents and normally encoun- -tered vibrationhave no effect .upon theiadhesion of the-letters.tothe support. I

Intthefdrawings:

Fig. 1 shows a sign embodying the invention; Fig. 2 shows a letterembodyingithe invention; imd

Fig. 3 shows'a'laminated letter 'embodying'the invention.

As seen in the: drawings,Fig. l represents a sign made up of the lettersand other decorative elements-according to the principlesof myinvention. In the' preferred form,the support panel I0 is made of glass.Ordinary window glass has a surface which is smooth enough to producehighly satisfactory results when employed in conjunction with my novelletters, and enameled 'metal plates are also satisfactory. .The..lettersor design elements L, seen in Fig. .2,l.have an undersurface ll which-issmooth..,and .polished. The-outer surface 12 maybe of any texturesuitable to display. I

,I have found that letters madeof flexible elastomeric vinyl plasticsheet material having a press-polished undersurface adhere toapaneof:glass or polished metalwith a great degree of tenacity.

'It is probable that the adhesionresults from :several factors. .Forexample, when the smooth surface H is pressed against the smooth panelI0, alarge art of the .air is excluded from between the surfaces,whereupon atmospheric pressure exertslan unbalanced force on theoutersurface of-the letters. .Withthis pressure, the coefficient of frictionbetween. the letters and the panel issufiicient to. retain the lettersin .mounted position against the force of gravity.

Itis also probable that due to the polished nature of the letter surfaceand of. thepanel, a certain degree of .molecularvadhesion is obtained.in-accordance .with the well-known principles of the Johannsen gaugeblocks and the like. Ihave experimented with mountingletters on a panelin .a bell. jar. and exhausting the air from the jar. I Even though theysurface of the letters wassmooth .to the touch without a semblance oftackiness and even. though the glass was perfectly clean and 5 dry, theletters remained mounted on the panel in v the vacuum.

' smooth molded or polished surface, it .will tend. to

adhere. in .the same manner. I-IoweverNI have found that the tenacity.of vthe. mounting when rubb eriarticlesmanufactured in accordance with-:.normalacommercialrpractice areemployedds not equal to that when theaforesaid synthetic plastic i letters are used; I 3 1:;assume:-Lthatv-theaadditional adhesion of the plastic material is due toone or both of two differences between letters formed of such materialand those formed of rubber. In the first place, the inyl plasticmaterials respond readily to the production of a very smooth orpress-polished finish, and according to the principles of my invention,the smoother the finish of the letters the greater will be the airpressure effects and the molecular adhesion referred to.

Secondly, it is probable that some of the plasticizer in the syntheticletters assists to increase the tenacity of the union. Although lettersformed according to my invention appear perfectly smooth to the touchand show no tendency to adhere to the fingers or clothes of the user, itmay be that upon pressing the smooth surface of the letters on thesmooth surface of the panel, a minute amount of plasticizer exudes andassists in augmenting the intimate engagement of the parts.

An example of one composition that I have found produces good results inas follows:

Composition by weight 100 parts of polyvinyl chloride (powdered resin)50 parts of dioctyl phthalate (plasticizer) 1 part of color pigment; forexample, Channel Black 0.5 part lead stearate 2 parts of a resinstabilizer blended together and the resulting mixture is then placed ona hot plastic or rubber mill and milled approximately ten minutes at 275F. This milling knits the mass into a homogeneous sheet of plastic. Themilled stock is then transferred to the cavity of a hot mold in ahydraulic press for press polishing. The interior of the mold has ahighly polished mirror-like surface, such as is produced by chromeplating and polishing. The press is closed and the plastic molded at 320F. for two minutes at approximately 100 p. s. i. pressure. Beforereducing the pressure the mold is cooled to room temperature. Thepressure is then released and the sheet removed from the mold. I moldthe sheet approximately .025" thick although thickner or thinnersections may be used. From this sheet the letters and designs may thenbe die cut.

Press-polished vinyl sheet or film might also conceivably be made bymolding or casting the vinyl resins in molds having a smooth surfacefrom solutions or dispersions of the plastic. The material might also beapplied as a thin coating on other materials such as wood, paper ormetal providing the mounting surface of the plastic material has asmooth, polished appearance or a smooth highly glossed surface. Forexample, a laminated letter L appears in Fig. 3 wherein a coating 20 ofthe plastic material is applied to a wood backing member 2|. Theunderside 22 of the composite letter is smooth and polished to effeetthe mode of operation described. If the backing member is flexible theletter is readily applied and removed, but if the backing member isrigid the letter should not be excessively large or the unit pressure ofapplication will be too low.

Other elastomeric viny1 polymers nad copolymers would prove suitable formy purpose. For example, a plasticized vinyl chloride-vinyl acetatecopolymer would work equally well. Certain rubber compounds will work toa lesser degree. The main disadvantage to the rubber compounds is thatthey lack a free plasticizer and it is diflicult to obtain the highlypolished surface required for best results. Consequently, greater effortis required to squeeze the rubber sheet against the smooth supportingsurface and obtain a good vacuum seal.

Although glass is considered to be an ideal background for the lettersand lends itself to illumination, I have found that any polishedmaterial or polished pane object will support the letterssatisfactorily. This includes objects with a smooth polished surfacecoat of vitreous or baked enamel or certain paints not subject tosoftening by migration of the plastlcizer. If compounded with anon-migrating plasticizer the letters could be used on any type ofpainted surface without any softening or damage to paint or to theletter. I find that display elements made as described may be pressedtogether with which a good union is effected. Thus, the panel couldcomprise an outer sheet of polished vinyl plastic or the like whichsheet may be applied to cloth, wood, paper, etc., having a smooth outersurface. The plastic material, like the letters themselves, may beapplied as a sheet of material fastened to the backing, or may be in theform of a coating for the backing.

Also, although I have explained at some length how to form a preferredkind of material, it will be understood that the claimsare notnecessarily limited to such material. The essence'of the invention is inthe provision of a design element having a surface formed of rubber-likeor elastomeric material having a smooth or polished surface, or alamination of such material with another material, which may be appliedto panes of glass or other panels having a similar smooth surface. Theterm polished surface as employed in the claims refers to a smooth orglossy surface whether producedby an actual polishing application, cast,molded, or the like.

Throughout the specification the display has been referred to usually asletters but it will be understood that the invention is not limited toletters of the alphabet because the purpose of the invention may beemployed regardless of the configuration of the applied object. Forexample, educational kits of letters, animals, objects, etc.. may bemade under the invention.

The terms elastomeric as used in this specification and the claims areterms generic to a class of synthetic substances having the propertiesof natural rubber, namely a very high deree of flexibility coupled withthe ability to return to its original dimension after a certain degreeof stretching. However, it is understood that the elasticity or percentelongation which produces no permanent set need not be anywhere near ashigh as that of natural rubber to carry out the present invention. Theterm includes synthetic plastic material including a 'plastloizer or itsequivalent and having the properties described necessary to effect theinvention.

Having thus described the present invention so that others skilled inthe art may understand and practice the same, I state that what I desireto secure by Letters Patent is defined in what is claimed. u

What is claimed is:

1. A character for use as a display element,

formed as a homogeneous element adapted to be attached to a glossysupport merely by application of slight pressure, said character beingformed of a synthetic resinous elastomeric material and including aplasticizer therefor substantially in the proportion of two parts ofelastomeric material and onepart of plasticizer, said charactercomprising a piece of flat, flexible, airimpervious plastic materialhaving at least one glossy, press polished, non-tacky surface by whichsaid character may be firmly attached to said support, the amount ofplasticizer in said material being sufficient to make the materialflexible for attachment as defined, but insufiicient to make thematerial flabby so as to be nonselfsupporting. i

2. A display comprising a support having a smooth, glossy,air-impervious surface, and a character formed as a homogeneous elementadapted to be attached to said support surface merely by the applicationof slight pressure, said character being formed of a synthetic resinouselastomeric material and including a plasticizer therefor substantiallyin the proportion of two parts of elastomeric material and one part of1.5

plasticizer, said character comprising a piece of fiat, flexible,air-impervious plastic material having at least one glossy, presspolished, non-tacky surface by which said character may be firmlyattached to said support, the amount of plasticizer in said materialbeing suflicient to make the material flexible for attachment asdefined, but insumcient to make the material flabby so as to benonself-supporting.

CHARLES N. DICKEY.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,530,997 Gjorup Mar. 24, 19252,046,924 Pendergast July 7, 1936 2,095,879 Kittredge et a1. Oct. 12,1937 2,200,203 Heintz May 7, 1940 2,293,887 Chamberlain Aug. 25, 19422,303,828 Derby Dec. 1, 1942 2,331,776 Heggedal Oct. 12, 1943 2,383,598Glidden Aug. 28, 1945 2,435,464 Radcliffe Feb. 3, 1948 FOREIGN PATENTSNumber Country Date 475,555 Great Britain Nov. 19, 1937 427,737 GreatBritain Apr. 23, 1935

